Here’s a quick case. Patient presents with urinary retention, Foley catheter placed, blood-tinged urine output. Initially the patient experiences great relief but gradually develops suprapubic discomfort again.


  1. What’s inside the bladder?
  2. What’s the bladder volume?
  3. How is that catheter working?
  4. What’s that bright echogenic arc coming of the superficial aspect of the Foley bulb?


The catheter was irrigated, and began to drain normally again after a blood clot was pushed out. The patient felt better, the urine flow cleared, and discharge with a leg bag and close urology follow up was arranged.

  1. A Foley bulb (bright echogenic circular structure) is visible inside the bladder
  2. Here’s an easy bladder volume calculation: Length x Width x Height x 0.75. Most machines will calculate volume based on your caliper measurements, but 3/4 of a cuboid isn’t that hard to remember
  3. Two ways to tell the catheter isn’t working:
    1. The bladder is pretty full despite a properly placed Foley bulb
    2. Your clinical acumen. Poor urine output, suprapubic discomfort…
  4. Grating lobe artifact. Note that the echogenic line is parallel to the curve of the transducer, and extends from a bright reflector out laterally from the main beam. Turning down the gain (especially the fair field gain) might reduce this a bit. Here’s a nice quick artifacts review.